# -*- coding: utf-8 -*-
# @Time    : 2021/3/20 9:05
# @Author  : lilu
# @Email   : 1906196327@qq.com
# @File    : 1到50内的整数和.py
# @Software: PyCharm

j = 0
for i in range(1,51):
    j += i
print(j)